Apparatus with ultra violet spectrum lamp, for the treatment of psoriasis

ABSTRACT

A phototherapy apparatus intended for the treatment of psoriasis comprising a dielectric-discharge excimer lamp with a spectrum which has a well-defined peak in the wavelength range around 308 nm; the lamp is mounted on a hinged or manoeuvrable arm supported by a stand.

[0001] Psoriasis is a non-contagious chronic skin disease, the cause ofwhich is still unknown and which is typically characterized by thick redzones of the skin which are covered with silvery or whitish scales. Theextent of the disease is variable, with small local areas or the wholeof the surface of the body being affected. The disease may also affectthe joints, nails and the mucous membranes.

[0002] Topical therapies are usually used for the less severe forms ofpsoriasis which are generally well defined and have the classicsymptoms. Creams and ointments with a pharmacological action(keratolytic agents, tar, dithranol, cortisone preparations,calcipotriol, tacalcitol, tazarotene) or simply softening agents areused.

[0003] Systemic therapies are used for the more severe forms or theforms of common psoriasis which do not respond to topical treatment.These are more complete and effective therapies since they are appliedto the whole of the organism. Precisely for this reason, however, theymay also cause notable side effects: it is essential, therefore, thatthey should always be administered under the close supervision of aspecialist doctor.

[0004] The most common systemic therapies use: methotrexate, cyclosporinA and retinoids. All these treatments give rise to significant sideeffects and contraindications which are well known in literature and tospecialists in the sector.

[0005] Phototherapy is also widely used.

[0006] Exposure to the sun has always been used for the treatment ofpsoriasis; it is therefore logical to imitate this using artificialsources so that it is readily available. Phototherapy is based on theapplication of ultraviolet radiation (UV). In the same way as visiblelight, which can be divided into the spectral colors ranging from violetto red, ultraviolet radiation can be divided into individual bands ofvarying wavelength. This division is performed on the basis of thebiological effect caused and thus the following three bands areobtained:

[0007] UV-C 100-280 nm: sterilization

[0008] UV-B 280-315 nm: skin erythema

[0009] UV-A 315-380 nm: skin pigmentation

[0010] The corneal layer absorbs most of the UV-B radiation which isthen totally absorbed by the malpighian layer and by the dermis. Themelanin absorbs, in addition to the heat, essentially the visibleradiation; only a part of the UV-A radiation and the visible radiationreaches the dermis, while the red and infrared light passes through theepidermis and dermis and reaches the hypodermis.

[0011] There was a notable increase in the use of light sources for thetreatment of psoriasis with the appearance of photochemotherapy (PUVA)which also awakened interest in other phototherapeutic methods. After afew years, however, the initial optimism regarding PUVA therapies wasreplaced by a certain skepticism; all the undesirable effects of thephotosensitizing drugs became evident and the long-term side effects ofthe drugs used were not clear.

[0012] Over the years it was demonstrated that all the therapeuticallyeffective radiant sources, including solar light (global radiation) usethe range of 297 to 315 nm. In 1980 Parrish showed, in his experimentsconducted on human beings, that the optimum efficiency in psoriasistreatment occurs in the range of 308 to 315 nm. This is the startingpoint of the principle of selective phototherapy, i.e. the use of alight source in which the spectral distribution of the energy contains awell-defined fraction of UV-B radiation (308-315 nm) necessary forobtaining the best therapeutic effect in the treatment of psoriasis.

[0013] At present two types of lamp are used: fluorescent lamps andmetal halogen lamps. The former have a wide active spectrum and must beused with filters which limit their spectrum, eliminating UVC and UVBradiation with a shorter wavelength; fluorescent tubes also have anemission with a wide spectrum and are limited to certain bands byspecific coverings.

[0014] Laser treatment of psoriasis has also been envisaged. Thissolution provides a very concentrated emission and therefore requiresscanning along the surface to be treated. The use of laser and theimplications of a concentrated emission mean that this solution is verycostly and that particular care on the part of the operator is alsorequired.

[0015] The solutions adopted hitherto also require the simultaneous useof drugs which may cause undesirable effects.

[0016] Moreover the use of coherent light, the wide nature of the rangeof radiation emitted and the use of corrective drugs are negativefactors as regards specific treatment of the skin disorder in question.

[0017] Taking this knowledge as its starting point, the invention hasbeen designed to optimize the therapy in question and simplify theoperations involved therein. Thus an apparatus has been developed suchas to allow the treatment, by means of radiation, of the patient's skin,in the zones to be treated, by means of a lamp which emits light with aspectrum which has a well-defined peak at the wavelength of 308 nm andwhich does not have undesirable effects.

[0018] Therefore, the subject of the present invention is a phototherapyapparatus intended for the treatment of psoriasis, which comprises adielectric-discharge excimer lamp which emits incoherent light with aspectrum which has a well-defined peak in the wavelength range around308 nm.

[0019] The dielectric-discharge excimer lamp is preferably equipped witha reflector and optical system for ensuring a substantially uniformdensity of energy in the abovementioned range, at a distance of about10-30 cm, on the skin of the patient to be treated.

[0020] Overall the apparatus comprises a stand and a hinged ormaneuverable arm or any other projecting support for the lamp which canmaintain the desired position and which extends from the stand so as toarrange the lamp in a suitable position with respect to the surface ofthe skin of the patient to be treated.

[0021] The apparatus is advantageously provided with a selective sensorfor stabilizing temporally—i.e. in an instantaneous manner—the intensityof emission in the spectrum range concentrated around 308 nm.

[0022] The excimer lamp emits incoherent light, provides an emission ofradiant energy which is not concentrated and able to allow the use ofconventional optical reflective and refractive means; on the conditionthat there is control of the operating temperature—which can be easilyachieved—this lamp concentrates the emission in the region of thedesired value of 308 nm; moreover it does not require the simultaneousadministration of drugs, thereby excluding undesirable effects. The formitself of the excimer lamp—extending in an elongated manner—allows easytreatment of surface zones, including large-size zones, with relativemovements of lamp and patient which can be easily obtained withoutdiscomfort for the patient. In addition, the cost is much lower thanthat of the apparatus which has hitherto been suggested in literatureand used.

[0023] The invention will be better understood with reference to thedescription and the attached drawing which shows a practicalnon-limiting example of the invention. In the drawing:

[0024]FIG. 1 shows schematically a possible structure of the apparatusfor the treatment of psoriasis; and

[0025]FIG. 2 shows a block diagram of said apparatus.

[0026] In the block diagram according to FIG. 2, 1 denotes thedielectric-discharge excimer lamp and associated accessories, inparticular a reflector and an optical system for obtaining uniformity ofthe energy irradiated onto the skin of the patient; 3 denotes anair-liquid exchanger with a de-ionizer having, associated with it, atemperature sensor 5 and a sensor 7 for the flow of the cooling fluid,in order to avoid fluctuations in temperature. 9 denotes the liquidcooling circuit for the lamp; 10 represents a selective optical sensor.The sensors 5, 7 and 10 are connected to a microcontroller 12 connectedto an operating panel 14, to a display 16 and to a printer 18. 20represents an electronic control unit and 22 a radiofrequency powersupply unit for the lamp 1.

[0027] Structurally speaking, as shown in FIG. 1, 24 denotes a stand, 26the hardware container for data processing, the management system, theradiofrequency power supply unit and the thermal conditioner. Thecontainer 26 also comprises the printer 18 and the control panel 30 forpresentation of the data. An arm 30 which is hinged or in any casemaneuverable and able to maintain the desired positions which areimparted to it in each case extends from the stand 24. The excimer lamp32 with optical reflector 34 and with optical system 36 for obtainingthe band of incoherent radiation used for the therapy is mounted on theend of said arm 30. The pipe 9 of the cooling circuit for the lamp, thecables for the lamp power supply and those for the sensors run along thesaid arm.

[0028] The apparatus uses the dielectric-discharge excimer lamp 32provided with the reflector 34 and the optical system 36 which have thefunction of directing and ensuring uniform density of the energy whichis emitted in the desired range and which must reach the skin of thepatient to be treated from a distance of about 10-30 cm. The lamp issupported by the arm 30 which, in the equilibrium condition, may bepositioned and fixed so as to remain in the desired position withrespect to the patient, standing or seated or lying on the bed, ifnecessary in successive positions which are required for treatment ofthe various zones of the skin to be irradiated.

[0029] The RF power supply system and the electronic control unit whichdetermines the emission at the desired wavelength and other componentsare driven by means of the microcontroller connected to the managementpanel which forms the interface with the operator. Control of theconstancy of the level of intensity at the desired wavelength—in theregion of 308 nm—is performed during feedback on the basis of the signalcaptured by the selective sensor centered on the desired wavelength. Theintensity of the emission and the dose delivered are read from thedisplay system of the machine/operator interface and recorded on aprinter with which the apparatus is equipped, together with patient'sdata and other useful information.

[0030] The optical systems for homogenization of the beam areinterchangeable with a group of systems of different construction so asto adapt the apparatus to the part of the patient to be treated.

[0031] The proposed system is suitable and may also be adapted for thetreatment of textile products in order to obtain color toning and/orother chemical-physical effects on fabrics or on yarns.

[0032] It is understood that the drawing shows only an example providedsolely by way of practical illustration of the invention, the forms andarrangements of said invention being able to vary without departing fromthe scope of the idea underlying the invention itself.

1. Phototherapy apparatus for the treatment of psoriasis, characterizedin that it comprises a dielectric-discharge excimer lamp, with aspectrum which has a well-defined peak in the range of wavelengthsaround the wavelength of 308 nm.
 2. Apparatus according to claim 1,characterized in that the dielectric-discharge excimer lamp is equippedwith reflector and optical system able to ensure a substantially uniformdensity of energy in the desired band, at a distance of about 10-30 cm,on the skin of the patient to be treated.
 3. Apparatus according to atleast claim 1, characterized in that it comprises a stand, an arm forthe lamp which can in any case be maneuvered and fixed in the positionsdesired in each case and extends from the stand so as to arrange thelamp in a suitable position with respect to the surface of the skin ofthe patient to be treated.
 4. Apparatus according to at least claim 1,characterized in that it comprises a selective sensor for stabilizing ineach instant the emission intensity in the spectrum range around 308 nm.5. Apparatus according to claim 1, characterized in that it comprises asensor for the flow of the cooling liquid, in order to preventtemperature fluctuations of the lamp.
 6. Apparatus with excimer lamp,for the treatment of psoriasis, all of which as described above andshown by way of example in the accompanying drawing.
 7. Apparatusaccording to claim 2, characterized in that the dielectric-dischargeexcimer lamp is equipped with reflector and optical system able toensure a substantially uniform density of energy in the desired band, ata distance of about 10-30 cm, on the skin of the patient to be treated.